Ritual suicide by disembowelment carried out by samurai. Literally means "stomach cutting." The samurai committing seppuku would shove a dagger such as a tanto into their stomach while another samurai acted as their second by lopping off their head.

Honorable suicide commited by Samurai after they have shamed themselves or are failed their masters. Samurai could be ordered to commit suicide by their lords (Daimyo)
The samurai would disembowel himself, and when the pain got to be too much to where he might shame himself, his second would decapitate him.

Seppuku is the ancient art of killing yourself if you get super pissed and can’t find anybody else to kill. Ninjas use all sorts of crap to kill themselves—guns, ropes, knives, lasers, spears, etc.—and don’t even think twice about it. These guys would kill themselves for just about any reason and often for no reason at all: that’s why we there are so few ninjas today.